Investigation into the Effects of Filler on the Mechanical Behavior of Bituminous Mortar

Abstract

The work presented in this article investigates the effect of filler type and filler
amount on the mechanical properties of bituminous mortar. The mortar comprises of filler,
binder and fine fractions of sand. As a base binder three kinds of polymer modified binders
were considered. The variables for the fillers included hydrated lime, backhouse fines and
filler amount in mortar. For each binder type seven different filler combinations were selected
resulting in a total of 21 mortar types. The mortars were then subjected to a 1000 hour long
term aging in a weatherometer. Then, the mechanical behavior of the aged mortars was
investigated using Dynamic Shear Rheometer (DSR). For DSR testing, a special test
geometry developed for mortar testing was utilized. For the various mortars, master curves
were constructed at a selected reference temperature using time-temperature superposition
principle. Based on the master curve results, the effects of varying the type and amount of
filler were analyzed. Analysis of the results showed that the use of hydrated lime resulted in
stiffening effect for two of the three binders. Increase of the filler amount resulted in increase
of complex modulus. The use of backhouse fines resulted in a decrease of complex modules
at high temperatures. The observed effects were generally binder dependent